how do I build a single app?

[Wojciech Puchar]

>
> I installed FreeBSD into a VirtualBox VM in January and started playing with the code. I must complement you people on the clarity of your code. I've enjoyed examining it.
>
> I wanted to try some code changes to some of the apps in the /bin directory, but can't figure out how to build a single app, or even build a single set of apps, like /usr/src/bin, /usr/src/sbin, /usr/src/usr.bin, or /usr/src/usr.sbin. Is there a way to do this, or do I just have to create my own Makefiles for each app I am experimenting on?

cd /usr/src/bin/program
make